This invention relates to an actuator element which forms a portion of a micro electro-mechanical device. The invention is herein described in the context of an ink jet printer but it will be appreciated that the application does have application to other micro electro-mechanical devices such as micro electro-mechanical pumps.
Micro electro-mechanical devices are becoming increasingly well known and normally are constructed by the employment of semi-conductor fabrication techniques. For a review of micro-mechanical devices consideration may be given to the article xe2x80x9cThe Broad Sweep of Integrated Micro Systemsxe2x80x9d by S. Tom Picraux and Paul J. McWhorter published December 1998 in IEEE Spectrum at pages 24 to 33.
One type of micro electro-mechanical device is the ink jet printing device from which ink is ejected by way of an ink ejection nozzle chamber. Many forms of the ink jet printing device are known. For a survey of the field, reference is made to an article by J Moore, xe2x80x9cNon-Impact Printing: Introduction and Historical Perspectivexe2x80x9d, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
A new form of ink jet printing has recently been developed by the present applicant, this being referred to as Micro Electro Mechanical Inkjet (MEMJET) technology. In one embodiment of the MEMJET technology, ink is ejected from an ink ejection nozzle chamber by a paddle or plunger which is moved toward an ejection nozzle of the chamber by an electro-mechanical actuator for ejecting drops of ink from the ejection nozzle chamber.
The present invention relates to an actuator element for use as an integrated component in the MEMJET technology and in other micro electro-mechanical devices.
The invention may be broadly defined as providing an actuator element as a portion of a micro electro-mechanical device, wherein the actuator element comprises a movable arm that is connected at one end to a substrate and which is formed at least in part from a titanium-aluminium nitride composition. The aluminium preferably is present in an amount not greater than 55% of the total titanium-aluminium composition and most preferably is present in an amount equal to about 20% of the total titanium-aluminium composition.
The movable arm of the actuator element preferably is formed by a sputter process as one step in a semi-conductor structure fabrication process. More specifically, the movable arm of the actuator element may be formed by reactively sputtering material from a titanium-aluminium alloy in the presence of nitrogen gas.